TNF-alpha gene expression in the liver of the IFN-gamma transgenic mouse with chronic active hepatitis

Cytokine gene expression in the liver of transgenic mouse which specifically expresses interferon-gamma gene (IFN-gamma) was measured using polymerase chain reaction analysis. IFN-gamma mRNA was found to be expressed in the transgenic mouse liver along with TNF-alpha mRNA. Messenger RNAs of CD4 and CD8, maturation markers of T cells, were expressed in both normal and transgenic mouse livers, indicating the presence of resident T cells. The level of CD4 and CD8 expression was slightly elevated in the transgenic mouse case, indicating an increased number of CD4+ and/or CD8+ T cells, but the lack of the activation marker IL-2 mRNA suggested a nonactivated state. TGF-beta 1 mRNA was expressed in both normal and transgenic mouse livers without any increase in the latter, and therefore does not appear to be involved in the development of chronic active hepatitis in this transgenic mouse. Since TNF-alpha is a terminal mediator of liver injury in several animal liver injury models, its high expression, presumably a result of the IFN-gamma which is transcribed from the introduced gene, might be involved in the development of chronic active hepatitis in this transgenic mouse.